Micromechanical modelling of the compression strength of three-dimensional integrated woven sandwich composites

This paper is concerned with a theoretical and experimental verification of a micromechanical model of newly developed sandwich panels denoted as 3D integrated woven sandwich composite panels. The integrated hollow core was made of a pile of 3D bars with a special configuration. Integrated woven sandwich composite panels consist of two fabric faces which were interwoven by pile fibers and therefore a very high skin core debonding resistance was obtained. With the objective of qualifying the mechanical properties of these structures, fairly extensive experimental research was carried out by investigators. Although some numerical methods have been developed to predict the mechanical behaviors of these structures, there are less analytical models in this area. Due to the computational difficulties and the time consuming nature of the finite element method, in the present study, a new micromechanics analytical model has been suggested for predicting the compressive strength of integrated woven sandwich composites. In order to evaluate the proposed model, fabricated samples with different pile heights and pile distribution densities were subjected to flatwise compression tests. The results show that compressive properties of integrated woven sandwich composite panels are decreased with the increase of core heights and increased greatly with that of the pile density. Furthermore, the micromechanics model reasonably predicted the compression strength, and there is a good agreement between the experimental data and model predictions.